A marking engine, or printer, is a device that receives a job and produces printed output. A bindery is a device that transforms printed output into printed product. For example, a pamphlet can be produced by printing the individual pages, collating them, and then binding them. Many printers print onto sheets that are then cut into individual pages. For example, United States currency is printed in sheets with each sheet having 32 pieces of currency. The bindery cuts the sheets into separate bills.
FIG. 6, labeled as “prior art”, illustrates a sheet 600 with eight different printing positions. After printing, the sheet 600 can be cut into eight units. The different print positions can contain the same printing pattern or can contain different printing patterns. For example, print position 1 601, print position 2 602, print position 3 603 and print position 4 604 can all contain a first printing pattern. Print position 5 605 and print position 6 606 can have a second printing pattern. Print position 7 607 can have a third printing pattern and print position 8 608 can have no printing pattern. Printing and cutting 500 sheets results in 2000 pages of print pattern 1, 1000 pages of print pattern 2, 500 pages of print pattern 3, and 500 pages of waste.
FIG. 7, labeled as “prior art”, illustrates a sheet 700 with three different printing positions. After printing, the sheet 700 can be cut into three units. Print position 1 701 is much larger than the other print positions. Print position 2 702 and print position 3 703 are the same size. As such, print position 1 701 can contain a large printing pattern while print position 2 702 and print position 3 703 can each contain the same small printing pattern. Printing and cutting 500 sheets results in 500 pages of the large printing pattern and 1000 pages of the smaller printing pattern.
The specific print patterns and where they are printed onto a sheet is called an imposition. The printer in the previous examples printed 500 sheets using each imposition. The printer does not need to be aware of how many or which printing patterns are present in an imposition. The bindery, however, does know. The bindery cuts the sheets and collects them to produce the different quantities of different printed product.
Historically, imposition referred to the process of setting up printing plates that were then used to print sheets. A person made the imposition by assembling the different print jobs and setting up the plates. Many modern printers use a xerographic process instead of printing plates. The imposition is transferred onto a plate or drum having an electrostatic charge over a photoreceptive surface. A light beam, such as a laser beam, selectively discharges the electrostatic charge to produce the imposition. An imposition is still produced, but in a far more efficient manner.
Modern imposition processes are automated to some level. Some processes are fully automated while others are partially automated. FIG. 6 presents an imposition where every printing pattern is the same size while FIG. 7 presents an imposition with different sized printing patterns. Systems and methods for creating impositions from like sized and differently sized printing patterns are known to those skilled in the arts of imposition, printing, and imposition algorithms.
Regardless of the efficiency obtained in producing the imposition, the efficiency of the bindery is unaffected. When given a set of jobs, a person chooses an imposition. Some impositions minimize bindery costs while others do not. As discussed above, cutting is a bindery operation. Sheets are cut in stacks. Cutting a stack of 500 sheets can cost nearly the same amount as cutting a stack of 10 sheets. Stacking sheets having different impositions is not a good solution because separating different products that are stacked together can be difficult and error prone. As such, systems and methods for creating impositions that allow for stacking large numbers of identical sheets without causing excessive waste are needed.